Remember, not everyone you ask to give will give, so even a modest crowdfunding campaign aiming to raise a few thousand dollars requires getting in front of thousands of people.
Unless you’re famous in your own right or have strong social influence, it’s unlikely you’ve got immediate access to a network of this size. Here’s where PR comes to the party.

A stretch goal is an extension of your target, where you specify the extra funds required to get your art to the next level.